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Fractions

What Are Fractions?

A fraction represents a part of a whole. It has two parts:

  • Numerator — the top number (how many parts you have)
  • Denominator — the bottom number (how many parts make a whole)
\[\frac{\text{numerator}}{\text{denominator}}\]

In nursing, fractions appear in medication labels, dosage calculations, and unit conversions.

Simplifying Fractions

Divide both numerator and denominator by their greatest common factor.

\[\frac{6}{8} = \frac{6 \div 2}{8 \div 2} = \frac{3}{4}\]

Multiplying Fractions

Multiply numerators together and denominators together.

\[\frac{1}{2} \times \frac{3}{4} = \frac{1 \times 3}{2 \times 4} = \frac{3}{8}\]

Dividing Fractions

Flip the second fraction and multiply.

\[\frac{1}{2} \div \frac{1}{4} = \frac{1}{2} \times \frac{4}{1} = \frac{4}{2} = 2\]

Adding and Subtracting Fractions

Fractions must have a common denominator first.

\[\frac{1}{4} + \frac{2}{4} = \frac{3}{4}\]

If denominators differ, find the least common denominator:

\[\frac{1}{4} + \frac{1}{2} = \frac{1}{4} + \frac{2}{4} = \frac{3}{4}\]

Clinical Application

Real World Context

Medication tablets are often scored for splitting. Understanding fractions helps you confidently calculate partial tablet doses.

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